Mariner V, now in the tenth day of its four-month flight to Venus, will fly by the planet at an altitude of about 2500 miles, project officials of the National Aeronautics and Space Administration and the Jet Propulsion Laboratory reported today.

Mariner was launched at 11:01 p.m. PDT on June 13 from Cape Kennedy and executed a mid-course maneuver at 4:08 p.m. on June 19.

Tracking data received at Deep Space Stations in California, Australia, Spain and South Africa and relayed to the command center at JPL in Pasadena, Calif., indicate that the trajectory correction maneuver was executed successfully.

Prior to the maneuver, Mariner's flight path would have taken it across the orbit of Venus some 42,000 miles from the planet's surface on October 18. The new trajectory, in addition to closing the distance, delays the Venus encounter some 15 hours to the desired time -- about 10:35 a.m. PDT October 19.

The sacecraft, at 12 noon PDT today, had traveled 13,859,132 miles of its nearly 217-million-mile trip. It was 1,588,936 miles from Earth and increasing its distance from Earth at a rate of 6609 miles per hour. On October 19, the communications distance between Venus and Earth will be 49.5 million miles.

Engineers at JPL reported that all Mariner systems are operating properly and that the spacecraft has responded to all commands generated by Mariner itself or transmitted from Earth.